1. Field of the Invention
This invention relates to laser-based methods and systems for enhancing optical breakdown.
2. Background Art
Much effort has been devoted to research on laser-induced optical breakdown (LIOB) since the advent of powerful lasers, because of the importance of LIOB in diverse fields including laser surgery, micromachining, three-dimensional optical data storage, solid state physics, etc. For example, U.S. Pat. No. 6,146,375 discloses a device for internal surface sclerostomy and U.S. Pat. No. 6,391,020 discloses a system for destroying material using optical radiation and ultrasound waves.
Recently, in order to obtain an in-depth understanding of the mechanism for LIOB and to find a controllable way for carrying out LIOB, extensive experimental and theoretical investigations have been focused on the laser parameter dependence of the breakdown threshold of optical materials and biological tissues. For example, U.S. Pat. No. RE 37,585 discloses a method to localize laser-induced breakdown.
The breakdown threshold, on the other hand, is also determined by the nature of the material itself. So far, much less attention has been paid to altering the breakdown threshold and achieving a controllable breakdown by modifying the material, although LIOB in well-designed materials has a wide range of potential applications.
Dendrimers are a class of macromolecules possessing a highly-branched three-dimensional architecture and well-controlled size, shape and functionality. U.S. Pat. No. 6,471,968 discloses a multifunctional nanodevice platform in the form of dendrimer complex.